Definition

What is Rubinstein-Taybi syndrome?

Rubinstein-Taybi syndrome (RSTS) is an extremely rare genetic pathological condition which is characterized by abnormalities in various organs systems of the body, including broad thumbs and toes, short stature, distinctive facial features, and varying degrees of intellectual disability.

How common is Rubinstein-Taybi syndrome?

RSTS is a rare disorder that affects males and females in equal numbers. The exact incidence of RSTS is unknown, although a study in the Netherlands estimates the incidence to be between one in 100,000 to one in 125,000 individuals. Please discuss with your doctor for further information.

Symptoms

What are the symptoms of Rubinstein-Taybi syndrome?

Generally, an individual with Rubinstein-Taybi syndrome will have intellectual disability, growth and developmental delays, problems with speech and communication, abnormally broad fingers and toes, abnormalities of the head and face.

Additionally, there are also abnormalities of the gastrointestinal system with feeding difficulties. Also, affected people’s bones of the thumb and toes may be malaligned.

When we break down the symptoms into the respective organ systems then the symptoms of Rubinstein-Taybi syndrome are:

Development

While prenatal growth is often normal, in most infants with RSTS parameters for height, weight, and head circumference fall below the fifth percentile during infancy. Affected infants fail to grow and gain weight at the expected rate (failure to thrive). Although weight gain can be very slow in infancy, children with RSTS may later show a relative obesity for their height. Feeding difficulties (dysphagia) may occur and many affected individuals are prone to repeated respiratory infections. As infants age, they may continue to experience poor growth and exhibit short stature (most below the third percentile).

The physical features seen in children with Rubinstein-Taybi Syndrome include:

A beak shaped nose

Agrimacing face

An abnormally small head

An underdeveloped upper jawand an abnormally small lower jaw

Eyes

There are also certain ocular abnormalities associated with Rubinstein-Taybi Syndrome. Such children will tend to have strabismus, ptosis, and epicanthal folds.

Musculoskeletal Deformities

Children with Rubinstein-Taybi syndrome tend to develop scoliosis as well as kyphosis as they grow. There may also be abnormalities of the vertebrae and the pelvis. These children tend to be prone to frequent dislocations of kneecap.

Genitourinary Tract

Abnormalities of the genitourinary tract are also one of the features of Rubinstein-Taybi Syndrome. Males with this disorder tend to have undescended testicles. They may also have an extra fold of skin at the base of the penis.

Some children also exhibit hypospadias in which the urinary opening is malpositioned. Renal abnormalities are also quite common.

The child may have a malfunctioning kidney or in some cases underdeveloped or absent kidneys which may lead to recurrent urinary tract infections, kidney stones, and abnormal accumulation of urine in the kidneys.

Cardiac

Pulmonary stenosis, patent ductus arteriosus and abnormal heart murmurs are some of the common conditions associated with a child with Rubinstein-Taybi syndrome. There are also other conditions such as entral septal defects and atrial septal defects happen to children with Rubinstein-Taybi Syndrome.

Respiratory (Lungs)

Affected individuals may also have abnormalities of the respiratory system. The lungs may be abnormally divided into small extra sections (lung lobulation) and/or the walls of the voice box (larynx) may be weak and easily collapsible, potentially resulting in swallowing and breathing difficulties (e.g., temporary cessation of normal breathing rhythm during sleep [sleep apnea]).

Behavior

Individuals with RSTS often exhibit a short attention span, decreased tolerance for noise and crowds, impulsivity, and moodiness. Autistic behaviors are common.

Increased Susceptibility

Some children with RSTS appear to be more prone to developing certain malignancies (including meningioma, pilomatixoma, rhabdomysarcoma, pheochromocytoma, neuroblastoma, medulloblastona, oligodendroglioma, leioyosarcoma, seminoma, odontoma, choristoma, and leukemia) than the general population.

Individuals with RSTS can be difficult to intubate because of the easily collapsibility of the laryngeal wall. An anesthesiologist comfortable with managing complex pediatric airway problems should administer general anesthesia when needed.

There may be some symptoms not listed above. If you have any concerns about a symptom, please consult your doctor.

When should I see my doctor?

If you or your loved one has any signs or symptoms listed above or you have any questions, please consult with your doctor. Everyone’s body acts differently. It is always best to discuss with your doctor what is best for your situation.

Causes

What causes Rubinstein-Taybi syndrome?

RSTS may be caused by a mutation in the CREBBP or EP300 gene, or as the result of a very small deletion (microdeletion) of genetic material from the short (p) arm of chromosome 16. In some people with RTS, the cause is unknown. Researchers believe that these cases are due to mutations in other genes that have not yet been identified.

Risk factors

What increases my risk for Rubinstein-Taybi syndrome?

Please consult with your doctor for further information.

Diagnosis & treatment

The information provided is not a substitute for any medical advice. ALWAYS consult with your doctor for more information.

How isRubinstein-Taybi syndrome diagnosed?

The diagnosis of RSTS is primarily based on physical (clinical) features, including a downward to the eyes (downslanted palpebral fissures), a low-hanging nasal septum (columella), a high palate, a grimacing smile, cusp-like structures (talon cusps) on the front teeth, and/or broad and angulated thumbs and great toes.

The diagnosis may be further supported through x-ray studies revealing malformations of the bones of the hands and feet characteristic to RSTS.

Genetic testing (FISH or sequence analysis) may confirm RSTS, including pathogenic variants in the CREBBP gene (identified in 50%-60% of affected individuals) or in the EP300 gene (identified in 3%-8% of RSTS individuals).

How is Rubinstein-Taybi syndrome treated?

The management of RSTS is directed toward the specific symptoms of each individual. Management may require the coordinated efforts of a team of specialists, including pediatricians, physicians who diagnose and treat heart abnormalities (cardiologists), skeletal abnormalities (orthopedists), hearing problems (audiologists), urinary tract abnormalities (urologists), kidney malformations (nephrologists), as well as dental specialists, physical therapists, speech pathologists, dietitians, and/or other health care professionals. Growth parameters should be regularly plotted on an RSTS-specific growth chart. There should be yearly eye and hearing evaluations and routine monitoring for cardiac, dental, and renal abnormalities.

Orthopedic surgery, physical therapy, and/or other supportive techniques may help treat certain skeletal abnormalities potentially associated with RSTS, such as scoliosis. In some cases, surgery may be performed on the hands and/or feet, particularly when there are extra (supernumerary) fingers and/or toes, or when the fingers are severely misaligned.